3D-printed meta-matching layer for enhanced ultrasound transmission through calcified plaques: a phantom study

Calcified plaques strongly reflect ultrasound waves, limiting visualization of structures located behind them. This proof-of-concept work presents one of the first demonstrations of a directly 3D-printed meta-matching layer (MML) designed for medical ultrasound frequencies (4 MHz) to improve transmission through calcified plaque-like structures. The MML employs subwavelength microstructures to create a gradient acoustic impedance, reducing reflections and enhancing acoustic transmission. Numerical optimization and experimental validation demonstrated strong agreement. At 4 MHz, the optimized 10- μ m-resolution MML increased relative transmission by approximately 192% and reduced relative reflection by approximately 77% compared with the aberrating layer alone. Ultrasound imaging confirmed improved signal penetration into the vessel lumen and preservation of downstream vessel visibility. Although image artifacts introduced by the structured interface currently limit robust flow quantification, this proof-of-concept study demonstrates the feasibility of patient-specific, add-on metamaterial layers for enhancing ultrasound transmission through highly reflective vascular structures.